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How Do Doctors Stage Dementia?

Updated: Jun 3, 2023

Do you or a loved one have Dementia, or does a doctor suspect that it may be Dementia? Generally speaking, screening tools are the first step in helping sort out the reasons why and to what degree someone may be having a cognitive challenge. Then depending on the results of those screeners, physicians may also suggest imaging tests, like CT, MRI, and PET scans, as well as test cerebral spinal fluid, blood, and other biomarkers to look for evidence of disease.

Because there’s no single test that can diagnose the cause of Dementia (which in and of itself is a syndrome and not a disease - it’s the result of a disease), doctors rule out various conditions, diseases, and disorders to determine their best diagnosis. Important note, pathological brain changes (those changes that physically affect the structure of the brain tissue, blood flow, neuronal connections, etc.) cause what we call Dementia, not the other way around.

No matter the underlying disease or diseases involved, if the cognitive impairments are sufficient and progressive enough most doctors will broadly call it Dementia. And if they can reliably attach a disease or disorder to it, they generally will, e.g., Dementia, likely caused by Alzheimer’s disease; Lewy Body Dementia or Dementia likely caused by vascular disease (major and/or mini-strokes typically), or Frontotemporal Degeneration, and others.

Hopefully, medical professionals can determine the cause(s) of the person’s Dementia and then use assessments to stage the condition. As the clinical symptoms of the underlying disease(s) progress, doctors continue to rely on those same assessment tools to determine how it is advancing. These tools may reveal whether someone has early-stage, middle-stage, or late-stage Dementia.

Results of these assessments may help doctors and family caregivers better manage someone’s condition and provide the appropriate support during each stage of Dementia.

You may hear doctors talk about the following commonly used assessment tools if you or a loved one has Dementia:

The FAST Scale

The Functional Assessment Staging Tool (FAST) scale helps doctors assess the cognitive well-being of older adults who may have Dementia. The scale runs from stage 1 – no subjective or objective cognitive difficulties – through stage 7f when someone can no longer speak, walk, sit up, smile or hold their head up independently.

To determine where someone falls on the FAST scale, doctors perform a physical examination and ask questions, either to the patient or a family caregiver. (When people have more advanced Dementia, doctors rely on answers from family members for essential details about their loved one’s capabilities.)

If a doctor determines that a patient has reached stage 7 on the FAST scale, they should be eligible for hospice care.

The BRCS Scale

During the Brief Cognitive Rating Scale (BCRS), a doctor asks a series of questions that fall into different categories – concentration, recent memory, past memory, orientation, and functioning/self-care. A patient may be asked to perform simple math equations in their head. They may be asked questions about what they had for breakfast, who the President is, and what the time and date are. They should also be asked about their ability to get around town without getting lost, plus how well they complete complex tasks like paying the bills and simple tasks like getting dressed.

Doctors rate a patient’s responses based on how well they answer the questions, then use the GDS scale to stage the patient’s cognitive function.

The GDS Scale

The Global Deterioration Scale (GDS) helps doctors determine a patient’s level of cognitive function after they complete a BCRS screening. The GDS runs from stage 1 – no cognitive decline – to stage 7, very severe cognitive decline. Stages 1, 2, and 3 are not considered Dementia, but stages 4 through 7 are, ranging from mild to severe.

Lisa Fields is a full-time freelance writer who specializes in health, psychology, sleep, nutrition, and fitness. Her work has been published by Reader’s Digest, WebMD, Women’s Health, Good Housekeeping, Self, and many other publications. Learn more about Lisa at

The opinions expressed by contributing authors are not necessarily the opinions of the Dementia Society, Inc. We do not endorse nor guarantee products, comments, suggestions, links, or other forms of the content contained within blog posts that have been provided to us with permission, paid or otherwise. Dementia Society does not provide medical advice. Please consult your doctor.

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